A SIMPLIFIED METHOD FOR NONINVASIVE ASSESSMENT OF VENTRICULAR RELAXATION BY CONTINUOUS-WAVE DOPPLER IN MITRAL REGURGITATION

Introduction and objectives. The minimum value of dP/dT is a parameter of diastolic function that can be estimated noninvasively by analyzin g the profile of velocity of the mitral regurgitant jet, recorded by c ontinuous-wave Doppler. This estimation requires a complex analysis of the curves that impedes its practical use. Our objective was to valid ate a simplified method to estimate noninvasively the value of dP/dT(m in) when mitral regurgitation exits. We calculated the pendient of the profile of velocity of the curve of mitral regurgitation during its d eceleration, between 3 and 1.5 m/s, an interval that defines a differe nce in pressure using the formula Delta p = (4v(1)(2) - 4v(2)(2)). We divided this interval by the time needed by the jet to decelerate from 3 to 1.5 m/s, obtaining the rate of pressure decay, in mmHg/s. Method s. We provoked mitral regurgitation in five pigs and registered dP/dT and the curve velocity of mitral regurgitation simultaneously, by micr omanometer-tipped catheter and continuous-wave Doppler, respectively. The rate of pressure decay was calculated on the mitral regurgitation curve. Results. We obtained 29 simultaneous registers. The coefficient for the correlationship between dP/dT and the rate of pressure decay was with an r value of 0.62 (p < 0.0001). The rate of pressure decay u nderestimated systematically the value of dP/dT. Intra and interobserv er variability of TDP was 9 and 11%, respectively. Conclusions. This s tudy validates a simplified method to estimate dP/dT noninvasively, wi th acceptable correlation with invasive measurements and adequate repr oductibility.